For root-level tasks, i.e., tasks which are members of the Tasks collection, the contents of this field will contain no value.
The database field referenced by the ParentTaskIdMember must be of a type that can be converted to the System.Guid data type.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2